The bioavailability of two ofloxacin (OFX) tablet formulations (OTT, test formulation from Laboratorio Atral SA - Portugal, and Tarivid, reference formulation from Hoechst AG - Germany) were compared in 24 (12M, 12F) healthy volunteers who received a single oral dose of 200 mg of each formulation in an open, randomized, two-period crossover fashion with a 14 day washout interval between doses. Plasma samples were obtained over a 24 h interval and OFX concentrations were determined by HPLC with UV detection. From the OFX plasma concentration vs time curves, the AUC([0-24]) (area under the concentration vs time curves from 0 to 24 h), AUC([0-infinity]) (area under the concentration vs time curves extrapolated to infinity), C-max (maximum concentration achieved), t(max) (time to achieve C-max), t(1/2) (terminal first order elimination half-life), and elimination constant (K-e) were obtained. All these variables were analyzed using both parametric and non-parametric statistics. The two OFX tablet brands did not show statistically significant differences in bioavailability as assessed by the statistical analysis of AUC([0-24]) (14.8 and 14.7 mu g h ml(-1), respectively for OTT and Tarivid), AUC([0-infinity]) (16.0 and 15.6 mu g h ml(-1)), C-max (2.9 and 3.1 mu g/ml), t(max) (0.8 and 1.5 h), t(1/2) (5.9 and 5.6 h), and K-e (0.12 and 0.13 h(-1)) values. Based on these results and on the United States Food and Drug Administration (FDA) requirements [1993], both formulations were considered to be bioequivalent.